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Bifidobacterium longum

Bifidobacterium longum

B. longum

BioticsMicrobiome & barrier

Aging is accompanied by a profound restructuring of the intestinal microbiota. Among the most documented changes is the progressive decline of bifidobacteria — early colonizers of the human intestine whose abundance reflects the state of the gut-immunity axis. Bifidobacterium longum is the bifidobacterium most closely associated with healthy longevity. Cohort analyses of centenarians from multiple world regions consistently identify B. longum among the microbial signatures of individuals who have surpassed 100 years of age — an association that raises questions about the mechanisms by which this microorganism contributes to maintaining immune balance across decades.

Last updated: March 25, 2026

Mechanism of Action

Tyndallised Bifidobacterium longum acts exclusively through its preserved cellular structures, without intestinal colonisation. Tyndallisation is a controlled heat treatment that inactivates bacterial cells while preserving intact their surface components: peptidoglycan, a constituent of the bacterial cell wall, and lipoteichoic acid (LTA). These structural molecules are recognised by TLR2 receptors (Toll-Like Receptor 2) expressed on epithelial and immune cells of the intestinal mucosa. This recognition triggers intracellular signalling that modulates the local immune response, reinforces protective mucus production, and stabilises tight junctions between epithelial cells. B. longum also influences the gut-brain axis through tryptophan metabolism and intestinal serotonergic signalling, which distinguishes this species from other bifidobacteria. Unlike a live probiotic, tyndallised cells do not produce active metabolites (short-chain fatty acids, lactate) since their metabolism is inactivated. Their biological activity is entirely mediated by these preserved cellular structures, which maintain their capacity to interact with immune receptors even after thermal inactivation.

Key Benefits

  • Strong

    A double-blind randomised controlled trial (n=200, 12 weeks) showed that the tyndallised form HT-ES1 of B. longum CECT 7347 significantly reduces the IBS Symptom Severity Score (IBS-SSS) versus placebo in adults with diarrhea-predominant IBS.

  • Moderate

    The tyndallised form of B. longum CECT 7347 preserves the capacity to modulate the innate immune response, reduce intestinal inflammation markers, and protect the epithelial barrier, as documented in cellular and in vivo models.

  • Emerging

    Multiple centenarian and supercentenarian cohort studies from different world regions identify B. longum as one of the most consistent microbial signatures of longevity, with significantly higher abundance than in younger adults.

  • Emerging

    A pilot trial in healthy adults (n=60, 8 weeks) showed an increase in butyrate-producing bacteria in the fecal microbiota and a reduction in total and non-HDL cholesterol after HT-ES1 supplementation.

  • Emerging

    Preliminary data suggest that B. longum influences the gut-brain axis through tryptophan metabolism and serotonergic signalling, with potential implications for well-being and sleep quality.

Dosage & Forms

The dose in this formula is 50 mg per day, corresponding to 5 billion equivalent cells (concentration: 100 billion per gram). This dosage exceeds the clinical reference dose of 2.5 billion cells used in the main randomised controlled trial on the tyndallised form HT-ES1, providing an additional comfort margin. It is important to note that the dosage of a tyndallised postbiotic should not be read as that of a live probiotic. Tyndallised cells do not need to "colonise" the intestine to act: their mechanism of action relies on the direct interaction of their cellular structures with immune receptors in the mucosa. Consistency of intake is more determinant than the amount ingested at any given time. Daily intake, ideally at the same time of day, optimises the continuous stimulation of mucosal TLR2 receptors.

In the Singular Formula

Inclusion rationale

Bifidobacterium longum is the bifidobacterium most closely associated with human longevity. Among bacterial genera, bifidobacteria colonise the intestine from birth and their proportion progressively declines with age — a phenomenon correlated with the decline of mucosal immunity and increased low-grade inflammation. Analyses spanning multiple independent centenarian cohorts from different world regions consistently identify B. longum among the most consistent microbial signatures in individuals who have surpassed 100 years. A recent systematic review (Food Science and Biotechnology, 2024) designates B. longum as the flagship strain of this association and analyses potential mechanisms: mucosal immunomodulation, gut-brain axis, inflammaging reduction. The tyndallised (postbiotic) form is not a degraded probiotic: tyndallisation preserves the active bacterial structures — peptidoglycan and lipoteichoic acid — that stimulate immune receptors in the mucosa without colonisation. A double-blind randomised controlled trial (n=200, 12 weeks) demonstrated significant efficacy of the tyndallised HT-ES1 form on digestive symptoms versus placebo. A pilot trial in healthy adults confirmed impact on microbiota composition, with an increase in butyrate-producing bacteria and a reduction in non-HDL cholesterol. In the formula, tyndallised B. longum acts synergistically with GOS (prebiotic fibres that selectively nourish endogenous bifidobacteria), Bacillus subtilis with complementary mechanisms, and Akkermansia muciniphila, specialist in mucosal barrier reinforcement.

Selected form

Bifidobacterium longum in tyndallised form (postbiotic), concentrated at 100 billion equivalent cells per gram. Tyndallisation is a controlled heat treatment that inactivates bacterial cells while fully preserving their structural components — cell wall, peptidoglycan, lipoteichoic acid. These components retain their capacity to interact with immune receptors in the intestinal mucosa. Unlike a live probiotic that requires refrigeration to maintain viability, this postbiotic is stable at room temperature and requires no cold chain. This superior stability ensures consistent biological activity throughout its shelf life. Quality: vegan, non-GMO.

Formula dosage

0 to 100 mg.

Synergies in the formula

Galacto-oligosaccharides (GOS) represent the most direct synergy with tyndallised B. longum. GOS are prebiotic fibres that selectively nourish endogenous bifidobacteria in the resident microbiota. This bifidogenic action increases the proportion of B. longum naturally present in the intestine, creating two-level coverage: the postbiotic provides immediate mucosal immune stimulation through its cellular structures, while GOS amplify the endogenous bacterial population of the same species over the long term. Bacillus subtilis, also present in the formula, is a transient strain with complementary mechanisms: it produces enzymes and antimicrobial compounds (bacteriocins) that contribute to microbial balance through a different pathway from B. longum. These two actors thus cover mucosal immunity through non-redundant mechanisms. Akkermansia muciniphila, the third microbial actor in the formula, specialises in reinforcing the intestinal mucus layer and epithelial barrier integrity. Combined with tyndallised B. longum acting on innate immunity, and GOS stimulating the endogenous microbiota, Akkermansia completes coherent functional coverage of the entire barrier-intestinal immunity axis.

Safety & Precautions

Bifidobacterium longum has a long history of safe use in human nutrition and supplementation. The tyndallised form presents a superior safety profile compared to the live form: since the cells are inactivated, any risk of unwanted bacterial proliferation is eliminated. No clinically significant drug interactions are documented. Unlike live probiotics, concurrent use with antibiotics does not affect the postbiotic's activity, as its cells are already inactivated. Supplementation is inadvisable in individuals with severe immunodeficiency (heavy immunosuppressive therapy, recent organ transplant), as a general precaution applicable to all ingredients of microbial origin — although this risk is significantly lower than with live forms. Pregnant or breastfeeding women are advised to consult their doctor before supplementation.

Scientific Studies

AuthorsYearTypeJournal

A randomized double-blind, placebo-controlled trial to evaluate the safety and efficacy of live Bifidobacterium longum CECT 7347 (ES1) and heat-treated Bifidobacterium longum CECT 7347 (HT-ES1) in participants with diarrhea-predominant irritable bowel syndrome

Double-blind randomised controlled trial (n=200, 12 weeks) comparing the live form ES1 and the tyndallised form HT-ES1 of B. longum CECT 7347 versus placebo in adults with diarrhea-predominant IBS. The HT-ES1 form showed a significant reduction in IBS-SSS score versus placebo.

Effect of Postbiotic Bifidobacterium longum CECT 7347 on Gastrointestinal Symptoms, Serum Biochemistry, and Intestinal Microbiota in Healthy Adults: A Randomised, Parallel, Double-Blind, Placebo-Controlled Pilot Study

Double-blind randomised pilot trial (n=60, 8 weeks) in healthy adults with mild-to-moderate digestive symptoms. HT-ES1 postbiotic supplementation increased butyrate-producing bacteria and significantly reduced total and non-HDL cholesterol versus placebo.

The role of Bifidobacterium in longevity and the future of probiotics

Systematic review exploring the link between bifidobacteria and human longevity. B. longum is identified as the strain most consistently associated with centenarians. The review analyses potential mechanisms (immunomodulation, gut-brain axis, anti-inflammaging) and therapeutic perspectives.

Consistent signatures in the human gut microbiome of longevous populations

Analysis of eight cohorts of longevous populations from different world regions. B. longum is among the most consistent microbial signatures in centenarians and supercentenarians, with significantly higher abundance than in younger adults from the same region.

Heat-Treated Bifidobacterium longum CECT-7347: A Whole-Cell Postbiotic with Antioxidant, Anti-Inflammatory, and Gut-Barrier Protection Properties

Preclinical study (Caenorhabditis elegans + HT-29 cell cultures) demonstrating that the tyndallised form of B. longum CECT-7347 retains its antioxidant, anti-inflammatory, and intestinal barrier-protective properties after thermal inactivation, through activation of innate immunity.

Frequently Asked Questions

Bifidobacterium longum: Postbiotic for Longevity | Singular